Effect of Hot Spring Therapy on Central Fatigue Elimination During Altitude Training

Sponsor
Macao Polytechnic University
Study ID
NCT07615478
Status
Recruiting
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Conditions

  • Altitude Training
  • Balneotherapy
  • Central Fatigue
  • Cognitive Impairment
  • Hydrotherapy
  • Sports Performance

Eligibility Criteria

Sex
ALL
Age
12 Years - 16 Years
Healthy Volunteers
Accepted

Interventions

  • Natural recovery — BEHAVIORAL
    Standard post-exercise recovery without water immersion. Participants rest passively in a thermoneutral environment (24°C, 50-60% humidity) for 20 minutes with ad libitum water and optional self-directed stretching. No heat, cold, or hydrotherapy interventions are applied.
  • Hot water immersion — BEHAVIORAL
    After exercise, full-body immersion in daily tap water. Temperature: 38°C ± 0.5°C. Duration: 20 minutes per session, 3 times per week (Tuesday, Thursday, Saturday at 16:00), for 4 consecutive weeks (total of 12 sessions). Protocol: Full-body immersion below the neck for 20 minutes, followed by a 10-minute rest before leaving the facility.
  • Hot spring balneotherapy — BEHAVIORAL
    After exercise, full-body immersion in natural hot spring water (pH approx. 7.4, Na+ 1210 mg/L, HCO3- approx. 3300 mg/L, total dissolved solids \>1000 mg/L). Temperature: 38°C ± 0.5°C. Duration: 20 minutes per session, 3 times per week (Tuesday, Thursday, Saturday at 16:00), for 4 consecutive weeks (12 sessions total). Protocol: Full-body immersion below the neck for 20 minutes, followed by a 10-minute rest before leaving the facility.

Study Details

This randomized controlled trial investigates the effects of hot spring balneotherapy on central fatigue elimination in adolescent rowers undergoing altitude training at approximately 1600 meters (Tengchong, Yunnan). Thirty adolescent athletes (aged 12-16 years) will be stratified by sex and randomly allocated to three groups: Group A (natural recovery, no immersion), Group B (38°C pure water immersion), and Group C (38°C sodium bicarbonate hot spring immersion). Interventions will be administered 3 times per week for 4 weeks. The primary outcomes are central fatigue indices including voluntary activation (VA) and central activation ratio (CAR). Secondary outcomes encompass cognitive function (Stroop test, Psychomotor Vigilance Test), cerebral hemodynamics (functional near-infrared spectroscopy, transcranial Doppler ultrasound), exercise performance (maximal oxygen uptake, 1000m test, 500m test), blood lactate, and hematological parameters (white blood cells, neutrophils, platelets).

Key Dates

First listed
May 29, 2026
Start date
May 25, 2026
Status verified
May 2026
Primary completion
Jun 25, 2026
Completion
Jun 25, 2026

Study Design

Enrollment
27 participants (estimated)
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT

Arms

  • Active Comparator: Natural Recovery Group
    Participants in Group A will undergo standardized rowing training at approximately 1600 meters altitude for 4 weeks. After each training session, participants will receive standard training recovery procedures without any water immersion intervention. Recovery includes passive rest, self-directed light stretching, and ad libitum hydration in a thermoneutral environment (room temperature 24°C) for 20 minutes. No thermal or hydrotherapy intervention will be provided.
  • Active Comparator: Hot water immersion group
    Subjects in Group B will undergo the same standardized rowing training at an altitude of approximately 1600 meters for 4 weeks. After each training session, subjects will receive whole-body immersion (below the neck, with the head above water) in daily tap water at 38°C ± 0.5°C for 20 minutes. The water temperature is monitored by a precision thermometer with an error of ≤ ±0.5°C. The immersion is conducted in a standardized indoor facility, and the time is 16:00 on Tuesday, Thursday, and Saturday.
  • Experimental: Hot Spring Immersion Group
    Participants in Group C will undergo the same standardized rowing training at approximately 1600 meters altitude for 4 weeks. After each training session, participants will receive full-body immersion (below neck, head above water) in natural hot spring water at 38°C ± 0.5°C for 20 minutes. The spring water has a pH of approximately 7.4, Na+ content of 1210 mg/L, and HCO3- content of approximately 3300 mg/L. Immersion will be performed in a standardized indoor facility on Tuesday, Thursday, and Saturday at 16:00, using the same protocol as Group B to maintain blinding.

Primary Outcome Measure

Voluntary Activation [ Time Frame: Baseline (Week 0), Week 2, Week 3, Week 4 (post-intervention), Follow-up (Week 1-2 post-altitude) ]

Central Contacts

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